Elongation testing machine



Malrcfzh 10, 1936. o. F. FREELAND 2,355,524

ELONGATION TESTINGA MACHINE original lFiled Aug. 1o, 1954 1N VENTOR.

@R1/a L E/ z-TELANQ BY v ATTORNEYS Patented Mar. 10, 1936 UNITED PATENTOFFICE Orville F. Freelaidg Msikeg'ii, Mich., assigimr to Anaconda .WireSa-Cable Gompany, N: Yana, corporationof Delaware New York,

739,212: D vided ixd this` aiililictioh June 8,

This application is a division of mycopending application forElongationtesting; rnachina Serial No. 739,212, iiled.August-,1Qj 193,45y

'I'he present invention is directed more particularly to theimprovements inth meansifor engagement with the end f a test pH yce.features of the present inventio` i fully apparent from the followingvsp y n when read in connection lwith the accompanying drawing,inwhicli;l

Fig. 1 is a longitudinal section through the testing machine shown in myabove identified parent application and illustrating the operativerelationship of the clamping mechanism of the test piece grippingmembers to the other parts of the mechanism; Fig. 2 is a plan view on anenlarged scale illustrating the clamp means and the arrangement forvarying the clamping movement thereof to compensate for different sizesof material to be handled.

The testing machine disclosed in my prior application above identified,of which this case is a division includes power means for putting thetest piece under tension and utilizes a stylus which travels at a ratecommensurate with the rate at which the piece on the test is elongated,such stylus being adapted to automatically move transversely when thetest piece is fractured. The stylus travels over a record sheet and,`therefore, makes a graph which reproduces the `movement of the V,tensionelement of the test machine and also records the point of the break orfracture.

The invention claimed in the present application relates particularly tothe gripping or jaw means for clamping the opposite ends of the wire tobe tested. These means include jaw members indicated generally at 28 and42.

A rack 24 is adapted to reciprocate a testI piece engaging member 26which carries suitable clamp jaws 28 adapted to be actuated by a lever30 in a manner hereinafter described, so as to clamp one end of the wireor other test piece 32. The member 26 is slidably supported on guiderods 34 secured to the frame members 36 and 38. A normally fixed testpiece engaging member 40 is provided with clamp jaws 42, which areactuated by lever 61. The movable test piece engaging member 26 haspivotally supported thereon a stylus supporting element 46 and, asshown, its pivotal support includes a stud 48.

A pen, pencil, or other suitable marking member, or stylus, as indicatedat 50, is secured to the end of the element 46 and a spring 52 isprovided which normally tends to press the stylus laterally against thework piece under test. As thus arranged, itis clear that when the workpiece being tested is fractured a transverse mark will be made tienesans.

The jaws 28 and 42 clamping the opposite ends of the wire or other pieceto be tested are preferably provided -with means whereby their movenientcontrolled to correspond substantially' with the'diameter of the wireunder test. The jaws are of substantially the same `construction and adescription of the right hand jaw shown in Fig. 2 Will sufce for both.These jaws are movable toward and from one another, a transverse keypiece 64 slidably engaging the two. One jaw member is pivotally securedto the short arm 66 of a lever 61 and the other jaw member is carried bya pair of parallel pivotally mounted links 68. Secured to the normallyiixed member 48, there is a projection 10, which is adapted to engage inone of a plurality of notches 'l2 of different depths formed in theperiphery of a rotatably mounted member 14. The member 40 is free toslide on the rods 34 and the springs 35 normally hold it in a desiredone of several iixed positions controlled by the setting of the notchedmember. Thus, an exact distance can be maintained between the clampmembers 28 and 44, regardless of the gauge of wire being tested.

It is important in a testing machine to maintain the same distancebetween the inner ends of the clamps 28 and 44 in order that auniformity of length of test piece can be maintained. For example, asdisclosed in the parent application, the test piece may be regarded ashaving a length of exactly ten inches. rlhis facilitates calibration ofthe chart on which' the test graph is made. Because the jaw memberscarried by the. re-latively xed member 48 partake of a slightlongitudinal movement due to their being mounted on pivoted links, it isapparent that unless some provision were made to compensate for thismovement, when wires or other test pieces of varying diameters were heldbetween the jaws, an exact length of test piece could not be maintained.By providing the member 'I4 with notches of variable depths, it will beapparent that as the member 'l0 carried by the member 48 coacts With thevarious notches to limit the movement of the member 40 under iniiuenceof the springs 35, that by properly diminishing the depths of saidnotches they may be so arranged as to maintain the proper spacingbetween the inner faces of the clamps in accordance with the varyingdiameters of wire adapted to be gripped thereby.

While I have described quite precisely the details of the embodiment ofthe invention illustrated it is to be understood that the detaileddisclosure is to be interpreted in an illustrative rather than alimiting sense since variousmodi flcations may be resorted to withoutdepal'ture from the invention as defined in the appended claims.

What I claim is:

1. An elongation testing machine of the character described comprisingspaced members one of which is normally fixed but which is initiallyadjustable, said one of said members having movable jaws for engagementwith the end of the test piece and said jaws being so mounted on saidone member as to partake of longitudinal movement in gripping testpieces of diiierent diameters and means for limiting the initialadjustment movement of said one of said members so as to compensate forsuch movement of the jaws, when such different test pieces are grippedthereby.

2. An elongation testing machine for wire or the like comprising spacedmembers one of which is normally xed but which is initiallyadjustable,one of said members having a pair of clamp jaws, links pivoted on saidone of said members and connected with said jaws, so that the latterpartake of longitudinal movement `in gripping test pieces of differentdiameters and means eiiective to determine the position of said one ofsaid members in accordance with the diameter `of material gripped bysaid jaws.

3. An elongation testing machine for wire and the like comprising spacedmembers, one of which is normally movable relatively to the other thelatter being normally xed but initially adjustable, clamping jaws havingrespective links pivoted thereto and to said other of said members, arotatably mounted element having a plurality of stop portions located atdiierent radial distances from the center of rotation thereof and meanson the member carrying said jaws which selectively coacts with said stopportions so as to control the position of the said normally fixedmember.

4. An elongation testing machine comprising one member adapted to bemoved to impose a load on the test piece, test piece gripping meansmovable with said member and adapted to grip one end of a test piece,another member normally iixed and carrying clamp jaws adapted to gripthe other end of a test piece, said jaws being so mounted as to partakeof a limited longitudinal movement in gripping test pieces of differentdiameters and means for varying the initial position of the secondmember so as to compensate for the longitudinal movement of the jawscarried thereby, whereby a predetermined fixed distance is maintainedbetween said members at the start of each test.

ORVILLE F. FREELAND.

